Given the fluctuations in green electricity generation, the future lies in combining solar power with battery storage. aream is therefore focusing on hybrid solutions: “They improve cost-effectiveness, stabilise the electricity grid and secure revenue despite volatile electricity prices”, says Patrick Lemcke-Braselmann, CEO of the aream Group.

aream is driving forward the transformation of its photovoltaic projects: in principle, all new PV systems over the next three years – totalling more than 1.2 GWp – will be implemented as hybrid projects in order to utilise the green electricity generated more flexibly.

After all, photovoltaic systems generate the majority of their electricity during the sunniest hours, particularly at midday between April and October. During this period, however, there is increasingly an oversupply of electricity, which often leads to negative market prices. Some systems must then be curtailed and are not permitted to feed electricity into the grid.

“Battery storage is the solution here”, says Lemcke-Braselmann. It enables the electricity generated to be temporarily stored and fed into the grid at a later time – for example, in the evening hours when prices are significantly higher. “This increases and further optimises revenues,” says Lemcke-Braselmann. For this reason, green electricity storage systems are a necessary prerequisite for economically viable PV projects. “Properly sized storage systems significantly increase value – even without special subsidy mechanisms or so-called innovation tariffs”, says Lemcke-Braselmann.

In addition, battery storage systems open up further sources of revenue by enabling participation in electricity markets for system services. This includes, in particular, the provision of positive secondary control power, i.e. the short-term injection of electricity to stabilise the grid frequency. Furthermore, these systems can also be used as instantaneous reserves, serving as a particularly rapid form of grid support.

The combination of PV systems and battery storage is particularly promising in Germany. According to the “European Co-location Markets Attractiveness Report” by Aurora Energy Research, Germany is the most attractive European market for operating a PV system and a battery storage unit at the same location or grid connection point. This is primarily due to the size of the German market and the “considerable potential” for rising returns. Lemcke-Braselmann: “With this strategy, we at aream are positioning ourselves for an energy system that is increasingly characterised by flexibility and intelligent control.”